Many specialist subjects are included in sub-categories; generalists and multi-specialists will be in alphabetical subcategories.

Book_Buyers	Mystery
Romance	Science_Fiction,_Fantasy_and_Horror
Antiques and Collecting	Arts
Biography	Book Auctions
Children	Computers
Entertainment	Facsimiles
Fiction	First Editions
Food	Gay, Lesbian, and Bisexual
Genealogy	History
Law	Local Interest
Military	Organizations
Recreation	Religion
Sciences	Search, Off-line
Search, On-line	Services
Sports	Textbooks
Transportation	Travel
Women